Power-driven components are becoming commonplace in motor vehicles as customers demand comfort and convenience. Power-actuated door latches and locks, hood releases, trunk openers, fuel-door openers, and hatches, for example, are either standard or optional equipment on many of today's cars and trucks. Customers looking to enhance their existing, non-powered equipment commonly turn to aftermarket components for conversion to power-driven equipment.
FIG. 1 is a perspective view of a known pull-type solenoid actuator 10, such as the type used to pull a cable or a latch or open a valve. The solenoid actuator 10 comprises a solenoid 11 and a plunger 13. The solenoid 11 comprises a coil 14, a housing 12, and a spring 15. The coil 14 is a long insulated wire wound with a helical pattern around a bobbin (not shown) defining a plunger bore 16. The wire is coupled to a voltage source by way of electrical conductors 17. The plunger 13 comprises an armature 18 and a stem 19. The stem 19 is adapted to be coupled to an external mechanism (not shown). The armature 18 comprises a magnetically-conductive material, such as, but not limited to, iron.
The solenoid actuator 10 coverts electrical energy to linear motion. Electrical activation of the solenoid 11 causes magnetic forces to act on the armature 18 to linearly translate the plunger 13 into the plunger bore 16 from a first position to a second position. When electrical energy is removed from the solenoid 11, the plunger 13 returns to the first position by the urging of the spring 15.
The linear motion of the plunger 13 can be used to power mechanisms that are normally manually operated from a first position to a second position. Examples of these mechanisms include the opening/closing and locking/unlocking of door latches, hood releases, trunk openers, fuel-door openers, and hatches.
The plungers 13 on known solenoid actuators 10 have a preset stroke that is not adjustable. The stroke is the distance that the plunger 13 moves between the un-energized and energized state. When energized, the plunger 13 is pulled into the bore 16 a predetermined distance defining the stroke.
The plungers 13 on known solenoid actuators 10 also have a preset plunger extension that is not adjustable. The plunger extension is the distance that the plunger 13 extends from an end of the solenoid 11.
Solenoid manufacturers must supply a plurality of solenoid actuator models with different strokes and different extensions to accommodate the various applications for which they are used. A starter motor, for example, requires a stroke of a particular distance, whereas a latching mechanism requires a stroke usually of a difference distance. This creates a great burden on the manufacturers and suppliers as a large inventory must be maintained to accommodate all of the solenoids of various strokes.
Solenoids also are specified with a rated force. The rated force is the amount of load that the solenoid actuator 10 is capable of providing the plunger 13 at the start of the stroke when energized. For example, the force required by a solenoid actuator 10 to engage a starter motor to an engine flywheel might be different than the force required to operate a door lock. The rated force is determined, in part, by the number of turns in the coil 14, the size of the plunger 13, the position of the plunger 13 relative to the coil 14, and the amount of current supplied to the coil 14. The number of turns in the coil 14, the size of the plunger 13, and the position of the plunger 13 relative to the coil 14, are constant for a given solenoid actuator 10, and the amount of current supplied to the coil 14 is typically a constant. Therefore, as in the case of stroke, the rated force is not adjustable.
Solenoid manufacturers must supply a plurality of solenoid models each with different rated force to accommodate the various applications for which they are used. This also creates a burden on the manufacturers and suppliers as a large inventory must be maintained to accommodate all of the solenoids of various rated forces. This burden is compounded greatly considering the combined specification of stroke and rated force. Economics of production and supply requires that a compromise be made which commonly results in the installer using a solenoid actuator that does not have an ideal specification for a particular application.
What is needed in the art is a solenoid actuator that has an adjustable stroke, adjustable rated force, and adjustable extension. This would help to alleviate the burden of manufacture and inventory as an adjustable solenoid actuator will be able to provide the stroke, rated force, and extension of multiple solenoid actuator models. Further, an adjustable solenoid actuator may be able to provide the stroke, rated force, and extension not currently being manufactured due to economic realities. An adjustable solenoid actuator would be especially advantageous for the automotive after-market parts industry as the adjustability would provide the installer with flexibility in installation on pre-existing components.